The VNA is the right instrument to analyze the loop and to understand if there is the right phase margin to get the oscillator starting and to get it stable.
BTW, in digital audio we are looking for short term stability, so if you read again the tool list you will find the right instrument to design a crystal oscillator.
An oscilloscope with its poor timebase is almost useless.
I haven't seen anyone using a cavity oscillator in audio yet.
BTW, in digital audio we are looking for short term stability, so if you read again the tool list you will find the right instrument to design a crystal oscillator.
An oscilloscope with its poor timebase is almost useless.
I haven't seen anyone using a cavity oscillator in audio yet.
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Half-right, is not right, and you do not have the power to make it right outside your home and your business
Not true what you say.
Impedance analyzer (which is a specific type of VNA+current sources, e.g. not Z0 referenced) is the right tool for loop measurements. Else, the trivial VNA will report S-parameters to the Z0. Now, all loops have Z0 at your measuring physical points and all frequencies? Never !
Yes, you can still re-scale the S-parameters obtained from a standard VNA, to give you the reality of the loop, but then you need postprocessing code&equations as I said.
Your "dislilke" of current sources based tools (modern ones), just because of your emotional impact with 70s era, is totally injust, technically incorrect, and in the end is your problem
Not true what you say.
Impedance analyzer (which is a specific type of VNA+current sources, e.g. not Z0 referenced) is the right tool for loop measurements. Else, the trivial VNA will report S-parameters to the Z0. Now, all loops have Z0 at your measuring physical points and all frequencies? Never !
Yes, you can still re-scale the S-parameters obtained from a standard VNA, to give you the reality of the loop, but then you need postprocessing code&equations as I said.
Your "dislilke" of current sources based tools (modern ones), just because of your emotional impact with 70s era, is totally injust, technically incorrect, and in the end is your problem
More you post, more it will backfire at your audio business. If I'm looking to buy your oscillator and read your posts on this forum, I would be like "That's it, I'm not buying anything made by this guy."
The VNA is supplied with a user manual. We have got and read the manual.
It looks like you have not yet found the right tool to measure (and design) a crystal oscillator in the list I have posted.
It's not so difficult since Wenzel, NDK, Crystek and so on use that specific tool.
BTW, please let me know the difference between the modern measurement tools and the ones from the 70s'
It looks like you have not yet found the right tool to measure (and design) a crystal oscillator in the list I have posted.
It's not so difficult since Wenzel, NDK, Crystek and so on use that specific tool.
BTW, please let me know the difference between the modern measurement tools and the ones from the 70s'
True, but my comments still right.
I thought you design MHz to GHz oscillators. Sorry, now I see that you mean designing of audio oscillators. Probably LCs or else (not cavity). Good luck.
I know your DIY-supported efforts for very good Qz oscillators. My prognosis was that you will come into my microave business, hence my suggestion for cavities. Sorry, I was wrong. I did not know that your Qz-thing has evolved into "your business" for audio, with such a little market (DIY is a small place). Must be that your overheads are huge, as explanation.
BTW, I obtained a deal for ppb-Qz with oven, from a geman company, for 80Eur/piece (lesser price if more quantity is asked). I have found no more drive to buy your solution (which I did not liked it in some technical details) which came also to about 60€, but more work and risks involved.
No, sorry. You tell me this difference, because you stamped the idea that a modern impedance analyser (ex. Bode 100 by Omron) is undesirable because if it has the current sources (NEEDED for impedance analysis) then is reminding you of 70s instruments. Childish (stubborn, limited) and confused.
We are not interested in microwave oscillators market, we have built the oscillator for ourselves.
Nor interest in audio business, we are poor hobbyist and not audio professionals.
And neither interest in ovenized oscillators, waste of time and money in digital audio.
However, I wonder how you can evaluate 60Eur / pcs when the crystal alone (< 100 pcs) costs more.
Time to sleep, another week of IT awaits me, the audio parentheses ends here.
Good night.
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Andrea, I am afraid that you will need to pay for this information
Good night myself
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Are you sure they have no global feedback? They are too good for an amp with no global feedback.
Hi Andrea,
Your instruments should be good enough to gain an understanding of what is going on in audio products. As Demian mentioned, sometimes you need a pile of instruments to answer specific questions even though you don't use them all the time. I have the very same situation.
All,
Most VNA instruments will work in spectrum analyzer mode. I have an impedance test jig for mine, but rarely need to evaluate parts at higher frequencies as they tend to misbehave at lower frequencies if they are going to be problematic.
What you need to do is evaluate what results you get for the various audio problems you run into. So get familiar with your gear. You don't always get a clean, pure THD or IMD plot for something that sounds good. Life isn't that simple.
As Demian said, the road to success is to make each piece of equipment as error free as you can. Everything else will fall into place. Why would you try and fix a room problem with the electronics? That is insanity. So if you want to confuse yourself with the silly notion that allowing something to misbehave because it might fix or counter something else that is misbehaving, you are truly insane.
In other words, fix the problems where they exist with the appropriate tools. Or you can run around waving your hands and get nowhere - it's all up to you. But don't argue or whine with people who are doing something about it with the equipment they need (and that includes a set of ears - okay?).
-Chris
Your instruments should be good enough to gain an understanding of what is going on in audio products. As Demian mentioned, sometimes you need a pile of instruments to answer specific questions even though you don't use them all the time. I have the very same situation.
All,
Most VNA instruments will work in spectrum analyzer mode. I have an impedance test jig for mine, but rarely need to evaluate parts at higher frequencies as they tend to misbehave at lower frequencies if they are going to be problematic.
What you need to do is evaluate what results you get for the various audio problems you run into. So get familiar with your gear. You don't always get a clean, pure THD or IMD plot for something that sounds good. Life isn't that simple.
As Demian said, the road to success is to make each piece of equipment as error free as you can. Everything else will fall into place. Why would you try and fix a room problem with the electronics? That is insanity. So if you want to confuse yourself with the silly notion that allowing something to misbehave because it might fix or counter something else that is misbehaving, you are truly insane.
In other words, fix the problems where they exist with the appropriate tools. Or you can run around waving your hands and get nowhere - it's all up to you. But don't argue or whine with people who are doing something about it with the equipment they need (and that includes a set of ears - okay?).
-Chris
Johnego,
They do not have any form of global feedback. The circuit type is inherently low distortion. Since I own a pair, I can report on their performance. They are used on a pair of PSB Stratus Gold speakers. 4 ohm with dips. I do plan to take the amps apart and see if I can improve them. (Mono X, original production)
-Chris
They do not have any form of global feedback. The circuit type is inherently low distortion. Since I own a pair, I can report on their performance. They are used on a pair of PSB Stratus Gold speakers. 4 ohm with dips. I do plan to take the amps apart and see if I can improve them. (Mono X, original production)
-Chris
If so then it is a very good amplifier...
I think later I will find out what topology they are using. From reading the web they mentioned it is a bipolar Emitter Follower but from what I could see somewhere else, the output is taken from the middle leg (Collector/Drain) so a CFP. May be different model...
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The sound will also be dependent on the impedance of the PSU and DF. Phase seems good, a phase plot of acoustic output vs freq should reveal more. Imaging is something that has a few characteristics that baffles me so not so sure, speaker and room properties also play a big part.
How much H2 as predistortion depends heavily on the driver being used, many found somewhere between 0.1 to 0.9 % to be optimum, perhaps 2-4% would be too much for the majority of drivers.
You need to note that the systems output is rarely measured, only the components in isolation. Logic dictates that an amplifier with lowest THD does not by default produce lowest THD acoustic output. I found that a system with better measurement does sound better and not flat, but that is arguably my preference or personal delusion I shall not extrapolate to others. Can not comment on systems with near perfect measurement since I have never heard any.
Thank you Chris, could you share the acceptable ways and tools you have verified to be appropriate in fixing driver induced distortion which is significantly higher than electronics? I am hopeful you can share something that I miss.
However, I feel predistortion to cancel electromechanical driver distortion is a valid method. Such trick is used in an RIAA preemphasis filter regularly used to counter electromechanical problems of vinyl record cutting and playback heads/transducers.
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I'm confused. The Bode 100 by Omicron (I have one) is a VNA with several optional hookups to measure impedance. Its really just math. No magic. But not suitable for very high impedance. They do show how to use a large resistor for higher impedances. it could be suitable for any VNA except at 100 MHz up VSWR becomes a real limitation.
For crystals something like the Saunders 150 crystal meter Crystal Impedance Meters will get you what you need to model and test crystals. They are not difficult to get. Easier than a VNA perhaps.
Because of:
1. Dishonest
2. Ego
No one will not admit that maybe their hearing ability are worst than other. And some people will not admit that maybe their knowledge is less than other.
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